Since my K40 laser came with a broken laser tube, I had to get a replacement. The new tube (real 40W tube) is 700mm instead of the original 630mm tube. I therefore had to enlargen the case.
Since the power side is opposite of the laser source, the extention needs to be properly grounded to avoid injury or even death by high voltage arcs.
The extention consists of a 3D printed shell for insulation and a standard hardware store part used in chimney installations, think enough to no melt when conduction high currents in case of a failure in the laser tube.
Link to an example part, as used in the photos: (non affiliate link)
https://www.amazon.de/dp/B075QD6J9L
The piping needs to be capped with several layers of aluminum tape or if possible be welded shut with a steel cap. I had to go for the layers of aluminum tape. (picture 1)
To ensure proper grounding of the steel pipe, you need to sand away the insulating paint on the case of the K40. (picture 2)
To ensure a secure connection I even lined the interface between K40 casing and the extention with aluminum tape (picture 3).
You must check continuity between case and extention!
After double checking continuity between the case, the extention and grounding wire, the lid can be glued at the end with two part epoxy.
The author marked this model as their own original creation.